Zoysiagrass plant named &#39;y2&#39;

ABSTRACT

An asexually reproduced variety of perennial zoysiagrass with a unique combination of morphological characters including medium leaf blade width and good persistence under low maintenance.

BACKGROUND OF THE INVENTION Field of Invention

The present invention relates to a new and distinct asexually reproduced variety of perennial zoysiagrass (Zoysia japonica (L.)) Merr.

BRIEF SUMMARY OF THE INVENTION

This invention relates to a new and distinct perennial zoysiagrass cultivar identified as ‘Y2’ zoysiagrass (herein referred to as ‘Y2’). The inventors, David L. Doguet and Virginia G. Lehman, discovered ‘Y2’ under cultivated conditions near Poteet, Tex. in a collection of plants from Kobe, Japan made by Jack Murray (deceased). ‘Y2’ was identified as a distinctly different vegetative patch or clonal plant differing by non-aggressiveness and quality under low maintenance from the surrounding plants. The inventors asexually reproduced ‘Y2’ by taking vegetative cuttings of stolons and rhizomes, cutting the rhizomes and stolons into segments, each with a vegetative bud, and rooting them in potting media.

For purposes of registration under the “International Convention for the Protection of New Varieties of Plants” (generally known by its French acronym as the UPOV Convention) and noting Section 1612 of the Manual of Plant Examining Procedure, it is proposed that the title of the invention is Zoysiagrass plant named ‘Y2’.

BRIEF DESCRIPTIONS OF THE ILLUSTRATIONS

FIG. 1. Plant of ‘Y2’ zoysiagrass showing stolon and tiller growth.

FIG. 2. Tiller of ‘Y2’ zoysiagrass showing few long leaf hairs.

COMPLETE DESCRIPTION OF THE VARIETY

‘Y2’ was characterized in greenhouse and field conditions. ‘Y2’ is a unique variety of zoysiagrass (Zoysia japonica (L.)) Merr. that Doguet and Lehman discovered under cultivated conditions near Poteet, Tex. Plants were grown from a collection of plants made by Jack Murray (deceased) from Kobe, Japan. ‘Y2’ was identified as a distinctly different vegetative patch or clonal plant differing in non-aggressiveness and quality under low maintenance from the surrounding plants. The plants were located in USDA Plant Hardiness Zone 8. ‘Y2’ was propagated by the inventors under field and greenhouse conditions by cutting of rhizomes and stolons, rooting them in soil, and planting of the rooted material to provide planting stock for studying performance and for comparison of morphological characters after propagation. ‘Y2’ has been propagated by rhizomes, stolons, tillers, and sod. Asexually reproduced plants of ‘Y2’ have remained stable and true to type through successive generations of propagation. No seedling establishment from ‘Y2’ has been noticed in either greenhouse or field studies.

‘Y2’ is a perennial zoysiagrass that spreads by both stolons and rhizomes. Characteristics of ‘Y2’ measured in 2005 were taken from plants that were approximately 15 months in age. The greenhouse was located near Lebanon, Oreg., with a nighttime low temperature of 50 degrees F., and daytime high of 80 degrees F., and a minimum soil temperature of 77 degrees F. The plants were grown with a minimum 14-hour day length, supplemented with photosynthetically active radiation equivalent to approximately 50% sunlight. The plants were fertilized with the equivalent of 1 pound of actual N per month, using a soluble fertilizer of 20-20-20 in two equal soluble applications per month.

‘Y2’ has a stiff leaf of medium length and medium width. ‘Y2’ has a shorter leaf than Crowne or BM230 (Table 1) when measured under greenhouse conditions in Lebanon, Oreg., 2005. ‘Y2’ has a longer floral area than ‘Diamond’ but a shorter floral area than Crowne or BM230 (Table 2). ‘Y2’ has few adaxial surface leaf hairs compared to the varieties ‘Cavalier’, ‘Palisades’, ‘Zorro’, or ‘Crowne’ that have many leaf hairs present (Table 3). No seeds of ‘Y2’ have developed; no seedlings have been noted in field production area or field test areas. The inflorescences produced in the greenhouse have consisted of empty glumes.

‘Y2’ has not shown susceptibility to the zoysiagrass mite in Poteet, Tex., where some susceptible varieties have shown symptoms of the mite. ‘Y2’ has shown some susceptibility to cool-weather brown patch. ‘Y2’ has shown resistance to Fall armyworm when adjacent Paspalum and Cynodon sp. plants have shown severe damage. ‘Y2’ has shown to excel with low maintenance inputs and is especially adaptable to areas such as bunker faces. ‘Y2’ has shown good turfgrass performance and temperature adaptation when tested as far north as Beltsville, Md., USDA hardiness zone 7a, which would extend the area of adaptation for ‘Y2’ in a line from northern Maryland across central Tennessee through northern Arkansas through Oklahoma in an East/West line and on a North/South line from Washington D.C., south through Mexico. ‘Y2’ will be limited only by winter survival in colder regions. ‘Y2’ is superior in survival under low maintenance conditions compared to ‘Zeon’ and ‘Jamur’ in water use demands as shown in test situations near Poteet, Tex., and will be limited by adequate precipitation in drier to arid regions. ‘Y2’ is adapted from sandy to heavier loam soil textures and from slightly acid to slightly alkaline soil pH. TABLE 1 Leaf blade widths and lengths and texture class of selected zoysiagrass cultivars, measured under greenhouse conditions in Lebanon, OR, 2005. Length, 4th Width, youngest 4th youngest Leaf crown leaf crown leaf Variety Stiffness cm mm Leaf Texture Class ‘Y2’ Very Stiff 1.27 1.56 Medium ‘Royal’ Medium — 0.78 Very Fine Stiff ‘Diamond’ Soft 0.85 0.92 Very Fine ‘Cavalier’ Medium — 0.55 Very Fine Stiff ‘Crowne’ Medium 3.39 3.01 Medium - Coarse Stiff BM 230 Medium 2.33 3.28 Coarse Stiff

TABLE 2 Inflorescence and leaf characters of selected zoysiagrass cultivars, measured under greenhouse conditions in Lebanon, OR, 2005. Length, flowering Sheath stem, from length, lowest node 4^(th) Stem width at Length to base floral crown Anther base of floral area region leaf length inflorescence Variety cm mm cm mm mm ‘Y2’ 1.67 3.7 1.55 1.16 0.81 ‘Cavalier’ — — 1.25 — — ‘Diamond’ 1.3  — 0.9 — — ‘Royal’ — — 1.43 — — ‘Palisades’ — — 4.15 — — ‘Crowne’ 3.05 11.0 3.05 — 0.71 ‘BM230’ 2.73 14.75 1.75 1.74 0.84

TABLE 3 Adaxial leaf hair length measurements of selected zoysiagrass cultivars, measured under greenhouse conditions in Lebanon, OR, 2005. Leaf hair, adaxial Presence/ Variety Number ‘Y2’ Few ‘Palisades’ Many ‘Zorro’ Many ‘Diamond’ Absent ‘Royal’ Absent ‘Crowne’ Many ‘Cavalier’ Many ‘BM230’ Absent

TABLE 4 Stolon characters of selected zoysiagrass cultivars, measured under greenhouse conditions in Lebanon, OR, 2005. Thickness Thickness Stolon Stolon 1^(st) 2nd Internode Internode Stolon youngest youngest length, 1^(st) length, Internode stolon stolon to 2^(nd) 2nd to 3^(rd) length, 3rd node node node node to 4th node Variety mm mm cm cm cm ‘Y2’ 1.56 1.96 1.03 1.06 1.13 ‘Cavalier’ 1.94 2.05 2.8 2.55 2.45 ‘Diamond’ 0.88 1.16 1.27 1.5 1.34 ‘Zorro’ 1.67 2.03 2.32 2.43 2.76 ‘Royal’ 1.65 1.84 2.1 2.28 2.17 ‘Palisades’ 2.05 2.19 2.93 4.28 5.35 ‘Crowne’ 2.13 2.27 3.2 2.43 2.95 ‘BM 230’ 2.05 2.24 — — —

COMPLETE BOTANICAL DESCRIPTION OF THE VARIETY

-   Origin: ‘Y2’ is a cultivar of a single clone discovered under     cultivated conditions in a Poteet, Tex. planting of zoysiagrass     clones derived from a collection of zoysiagrasses from Kobe, Japan     made by Jack Murray (deceased). -   Classification: Zoysia japonica (L.) Merr.     -   -   Growth habit.—‘Y2’ is a perennial plant that spreads by             stolons and rhizomes and produces a dense, fine textured             turfgrass. The inflorescence of ‘Y2’ is a terminal             spike-like raceme, with spikelets on short pedicels.         -   Leaf Blade.—rolled in the bud, concave surface.         -   Leaf blade pubescence.—1 to 25 hairs on adaxial surface,             none on abaxial surface.         -   Leaf sheath pubescence.—absent, except for a few long hairs             at mouth of sheath, mean length sheath hairs: Y2: 3.41 mm;             Zorro: 4.47 mm; Cavalier: 4.41 mm; BM230: 5.68 mm; Royal:             4.33 mm; Palisades: 3.51 mm.         -   Leaf blade margin.—Y2=semi-rough; BM230=rough;             Cavalier=mostly smooth.         -   Leaf blade veins.—obscure.         -   Leaf blade flexibility (softness).—very stiff.         -   Vegetative leaf, 2nd youngest vegetative leaf, non-flowering             stolon.—Blade length range: Y2: 0.7 cm to 2.3 cm, mean             length: 1.74 cm; Zorro: 0.3 to 3 cm, mean length: 1.78 cm;             Royal: 0.5 to 2.4 cm, mean length: 1.23; Palisades: 1.4 to             11.7 cm, mean length: 7.62 cm Blade width mean: Y2: 1.28 mm             to 2.4 mm, mean width: 2.09 mm; Zorro: 0.97 to 2.24 mm, mean             width: 1.76; Royal: 1.06 to 2.1 mm, mean width: 1.63;             Palisades: 2.9 mm to 5 mm, mean width: 3.91.         -   Sheath length mean, 4th youngest vegetative leaf.—Range: 0.9             to 2.8 cm, mean length: 1.55 cm; mean, Cavalier: 1.25.         -   Stolon leaf angle, third youngest leaf.—Y2: 78.3; Zorro:             71.4; Cavalier: 80.8; Crowne: 109; BM230: 91.5. -   Inflorescence characters:     -   -   Culm total length, including floral area to node below flag             leaf.—5.3 cm. Length of stem of inflorescence: Y2: 3.7 cm             Floral area length: Y2: 1.67 cm; BM230: 2.73 cm.         -   Culm width, stem thickness, base of floral area.—0.57 mm.         -   Anther length.—1.16 mm.         -   Floret (seed) length.—2.54 mm.         -   Floret (seed) width.—0.91 mm.         -   Node thickness, node below inflorescence.—Y2: 0.98 mm;             BM230: 1.21 mm.         -   Pedicel length.—1.16 mm.         -   Flag leaf length.—Y2: 0.3 cm; Crowne: 1.53 cm.         -   Flag leaf width.—0.57 mm; Crowne: 1.41 mm. -   Mature plant height, including inflorescence: Y2: 4.89 cm; Crowne:     14.6 cm; BM230: 22 cm. -   Color notations, vegetative characters, based on The R.H.S. Colour     Chart (light quality, photoperiod, and general growth of the plants     affect color notations):     -   -   Leaf blade color adaxial leaf surface.—137 C green.         -   Leaf blade color abaxial leaf surface.—146A yellow green.         -   Stolon Color.—145A yellow green; with cool temperatures,             will show anthocyanin Purpling, 67A red purple. -   Color notations, floral characters, based on The R.H.S. Colour Chart     (light quality, photoperiod, and general growth of the plants affect     color notations):     -   -   Culm stalk.—137C green.         -   Stigma.—155A white.         -   Anthers, fresh.—N77A purple.         -   Anthers, mature, dried.—N99D grey brown.

REFERENCES CITED

U.S. Patent Documents October, 1998. Engelke, M. C. U.S. PP 10,636. ‘Diamond’ zoysiagrass October, 2000. Engelke, M. C. U.S. PP 11,570. ‘Crowne’ zoysiagrass December, 1986. Youngner, V. B. U.S. PP 5,845. ‘El Toro’ zoysiagrass September, 2000. Engelke, M. C. U.S. PP 11,515. ‘Palisades’ zoysiagrass 

1. A new and distinct variety of zoysiagrass plant, substantially as described and illustrated herein, characterized particularly by a unique combination of morphological characters. 